Download Catheter-based management of aortic valve

Catheter-based management of aortic valve regurgitation in experimental
cardiology
Jan Sochman1),2), Jan H. Peregrin2),3)
1)
Clinic of Cardiology, Institute for Clinical and Experimental Medicine, Prague,
2)
Center for Cardiovascular Research, Prague, Czech Republic,
3)
Department for Radiodiagnostic and Interventional Radiology, Prague, Czech
Republic
Correspondence to: Jan Sochman, Clinic of Cardiology, IKEM, Videnska 1958/9, 146 22
Prague 4, Czech Republic.
E-mail: [email protected]
Short title: catheter-based heart valve management in experiment
Textové informace: 8 stran textu, 5 stran literatury, 4 obrázky s korespondujícími legendami,
0 tabulek
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Summary
Non-surgical management of aortic valve disease has been given considerable attention.
There have been several initial publications recently reporting its use in clinical practice.
The main issue is to get an understanding of the pathophysiological processes and, most
importantly, extensive experimental activity. In addition to testing of various animal
models, technical and material aspects are also being intensively investigated. It is not
clear yet whether the durability and applicability of this promising development will be
comparable with the standard of current cardiac surgery. Nonetheless, even the use of
some of the models as a temporary approach helping to improve the circulatory status,
not allowing safe surgery, is certainly justified. At any rate, a new stage of research and
clinical application has set off. Still, experimental background continues to be simply
indispensable. The paper is a short review of the issue.
Key words: Aortic valve regurgitation, experimental research, catheterization
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Elementary physiology and pathophysiology of the aortic valve
The left ventricle generates a pressure under which a certain amount of blood is
transported behind the aortic valve. Ideally, none of the expelled volume returns behind
the valve. Trace regurgitation, demonstrable solely using auxiliary imaging techniques
(e.g., by echocardiography) need not necessarily, in the presence of an otherwise normal
finding, a deviation from the physiological range. However, the transport of blood from
the ventricle to the circulation does not occur completely unopposed. It is opposed by
hydrostatic pressure from area situated at a level higher than the left ventricle and, most
importantly, by resistance of the large vessels (whose elastic properties allow the shift of
the pulse wave) and resistance of the vascular capacitance bed, which may additionally
alter its own vasomotor characteristics thus significantly affecting the resistance. The
resistance created in such a way generates a pressure shock, which passively closes the
aortic orifice and provides rough information dealing with diastolic pressure. Under
physiological conditions at rest, the systolic/diastolic difference is not in excess of 100
mmHg. Aortic valve disease may be due either to orifice narrowing or loss of functional
valve closure. In the former case, pressure-type of heart failure with respect to the
prolonged period of time sets in with a component of relatively long-lasting
compensatory mechanisms. In the latter case, the compensatory process is made shorter
by the component of left ventricular hypertrophy, with the volume type of heart failure
possibly developing in the future. There are situations whereby both impairments
combine. Likewise, there are conditions whereby aortic valve disease develops quickly
or, more often, whereby all factors of physiological compensation are suddenly
exhausted. It is in these cases that radical management is considered. While the current
therapeutic standard is cardiac surgery, catheterization-based approaches have been
proposed. However, these approaches continue to be essentially derived from
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experimental techniques. This text is a brief overview of the development of
experimental methods modulating aortic valve disease, and aortic regurgitation in
particular. At the same time, it is critical to balance neatly between views perceiving
catheter-based approaches as definitive therapy and approaches, which are only
transient. Definitive catheter-based management of aortic insufficiency has not been
completely defined. One simply cannot copy the situation seen during pulmonary artery
valve disease. Current catheter-based techniques are only applicable in cases whereby
surgical management is not safe given the situation. Once hemodynamic status has
improved as a result of the catheter-based approach, it is possible to consider a
definitive surgical solution proven by current therapy.
Historical overview
Efforts over the past 40 years at creating a catheter-based cardiac valve replacement
have evolved from experimental work to initial clinical application. Initially, these
efforts were aimed at managing valve diseases in tubular structures such as the
pulmonary artery or the aorta. The idea was to provide temporary support to the failing
myocardium and reduce the impact of heart failure on organs so eventual improvement
could be followed by a definitive surgical treatment. Clearly, there has been a paralled
effort to manage the valve problem not temporarily, but permantly using a direct
catheter-based approach. In regards to valve regurgitation, the issue is not homogenous.
One option of management is focused on techniques modifying the orifice per se and the
second one is represented by valve-replacing techniques. Very often, the procedures
require the close cooperation of an interventionalist with the surgeon. The text below
examines some techniques employed in the presence of valve regurgitation as related to
their basic shape structure and experimental data as well as technical valve designs and
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overall philosophy governing their use. We are no doubt at the start of new techniques
where only the future will show how much these steps have been successful. Use of a
catheter-based techniques is logically justified only in cases where it is necessary to
bridge the period to safe surgery (provisional catheter-based treatment) or in cases
where current techniques have been shown to be effective and durable for a period
comparable with that of surgery (i.e., roughly more than five years). Experimental
background has been essential.
Aortic valve parameters
Aortic valve fits into the tubular structures problems. The valve apparatus consists of
three well defined leaflets with definitive passive motion during systole and diastole. Due
to relatively high systolic and diastolic pressure the aortic valve is confronted with a
relatively high mechanical stress and, in terms of morphology, consideration is to be
made of the relation to origin of the coronary arteries. The movement of the tube during
systole and diastole in all directions is very limited. Most of all useful parameters is
derived from echocardiography followed by MR imaging or contrast aortography. Here
again, the key considerations are the diameters of the aortic valve orifice and of the
adjoining segment of the ascending aorta.
Aortic valve regurgitation
Experimental efforts and proposed designs seeking reduction or complete elimination
of aortic regurgitation date back more than four decades ago. Initial studies were based
on the fact verified surgically that the valve can also be placed in a supra-coronary
position (Hufnagel and Harvey 1953, Hufnagel et al. 1954, Harken et al. 1960). Optional
positions of the aortic prosthesis placed using a catheter-based procedure could be
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described in relation to virtual line of leaflet coaptation. The choice is as follows:
supracoronary and infracoronary, orthotopic or heterotopic.
Experimental models
All initial designs made use of the mechanical components. The pioneering work
apparently dates back to 1965 (Davies 1965) providing for a temporary solution to aortic
regurgitation. This was followed by a number of proposed techniques, all essentially a
modification of the original idea whereby a catheter is temporarily advanced to the
aortic region and its modification should reduce or, ideally, completely stop the
regurgitating blood flow (Moulopoulos et al. 1971, Moulopoulos 1972, Philips et al. 1976,
Boretos and Poirier 1977, Matsubara et al. 1992). The specific idea was to use the
intraaortic balloon pump with a timing different from that used conventionally
(Moulopoulos et al. 1980). A completely revolutionizing approach was published in 1992,
fully eliminating the previously advanced cathether as an anchoring mechanism. The
new design remotely resembled a stent at one end and the cage of a surgically used ball
mechanical prosthesis at the other (Pavcnik et al. 1992). The whole prosthesis was
implanted in two steps: first, the actual cage carrier and, second, a detachable balloon
filled with a fluid with an admixture of a contrast medium (Fig.1).
This was followed by a series of investigations, which already divided the next
approaches to a purely mechanical prostheses implanted using a catheter, bioprostheses
implanted using the same technique, and hybrid approaches. In our department, we
tested the purely mechanical prostheses in a two-stage experiment, with the stent carrier
inserted first to be followed by valve disc placement (Sochman et al. 2000)(Fig.2).
This was already an imitation of the model of disc prosthesis proven by surgical
practice. From a family of catheter-implantable biprostheses as well as from a historical
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overview, some approaches affecting clinical practice could be quoted (Andersen et al.
1992, Moazami et al. 1996, Boudjemline et al. 2002, Boudjemline and Bonhoeffer 2002,
Lutter et al. 2002, Boudjemline and Bonhoeffer 2002, Boudjemline and Bonhoeffer 2003,
Huber et al. 2004). While the advantage of this model was prosthesis implantation at the
time, its drawback was the relatively bigger caliber of the instrumentarium. The above
techniques made use of a stent carrier, which had to be dilated during deployment by a
balloon catheter. However, there are designs using a self-expandable carrier with an
anchored biological valve (Ferrari et al. 2004). Besides, hybrids have been developed
which, while seeking to resemble, in their design, the shape of the native valve, made use
of plastic membranes of most varied properties (Hilbert et al. 1987, Lo et al. 1988).
Currently, a new option is being tested experimently whereby the membrane component
of the valve is not made of plastic or conventional biological material (pericardium,
homogenized animal valve, etc.). Instead, the material used is small intestinal submucosa
(Pavcnik et al. 2001). Because of material duration and biodegradability characteristics,
research has again focused on an area showing less demands on mechanical stress (Ruiz
et al. 2005). Presently, the bioprosthetic models clearly predominate. Their advantages
includes the orthotopic position (i.e., infracoronary and valvular with respect to the
annular position). However, mechanical prostheses, which are used less often, have
improved in being capable of being estabishled at the time, as is the case of bioprotheses
(Sochman et al. 2006). However, their position is supracoronary (i.e., supravalvular in
relation to the annulus) (Fig.3).
We are currently testing a completely different – infracoronary and infravalvular mechanical prosthesis position. First experiments were encouraging (Fig. 4).
Purely catheter-based options in clinic application
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There are at present initial papers reporting catheter-based therapy also in man. Quite
surprisingly, the problem was not aortic regurgitation but aortic stenosis in the group of
so–called “no-option treatment” patients. They were patients not indicated for surgical
therapy because it was considered too risky; moreover, they were patients at an
advanced age. In addition, aortic balloon valvuloplasty, as previously considered, was no
longer concerned. In this particular case, a stent carrier with a biological valve was
introduced into the aortic orifice, with the stent carrier pushed into the aortic wall using
the balloon in orthotopic position. Initial results are said to be most encouraging
(Cribier et al. 2002, Cribier et al. 2004, Bauer et al. 2004, Hanzel et al. 2005, Grube et al.
2005). Still, nothing is known about the durability of the above measure.
Potential role for catheter-based managements
There is no doubt that the key method for managing any valve disease is surgery. This is
supported by time-proven clinical practice, declared outcomes and undisputed
durability. Still, the era of catheter-based therapy has begun: in some centers, it is most
successful option, in other centers, it has not moved past the experimental stage In still
other centers, it is the object of skepticism, critique or concern. However, if it does
handle a temporary problem making safe surgery unfeasible, it should be accepted. This
applies in particular to acute and life-threatening states. Logically, one should conclude
that a biological prosthesis is not the only solution. In non-acute cases, other logical
requirements are to be met in addition to the clear-cut requirement ruling out “major
surgery“. These requirments include reliability and feasibility in an acceptable form
and, most importantly, outcome durability. However, only the future will tell. At any
rate, there will be no progress without experimental work.
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Acknowledgment
This work was supported by the Institute for Clinical and Experimental Medicine
(reserch project Nr. # 00023001 awarded by the Ministry of Health) as well as by
research grant awarded by Ministry of Education, Youth and Sports (reg. Nr. #
1M6798582302).
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References:
ANDERSEN HR, KNUDSEN LL, HASENKAM JM: Transluminal implantation of
artificial heart valves: description of a new expandable aortic valve and initial results
with implantation by catheter technique in closed chest pig. Eur Heart J 13:704-708,
1992.
BAUER F, ELTCHANINOFF H, TRON CH, LESSAULT PF, AGATIELLO C,
NERCOLINI D, DERUMEAUX G, CRIBIER A: Acute improvement in global and
regional left ventricular systolic function after percutaneous heart valve implantation in
patients with symptomatic aortic stenosis. Circulation 110: 473-476, 2004.
BORETOS JW, POIRIER RA: Aortic valve catheter. United States patent Nr.
4 056 854, 1977.
BOUDJEMLINE Y, BONHOEFFER P: Percutaneous implantation of a valve in the
descending aorta in lambs. Eur Heart J 23: 1045-1049, 2002.
BOUDJEMLINE Y, BONHOEFFER P: Percutaneous valve insertion: a new approach?
J Thorac Cardiovasc Surg 125:741-742, 2003.
BOUDJEMLINE Y, BONHOEFFER P: Steps towards percutaneous aortic valve
replacement. Circulation 105: 775-778, 2002.
BOUDJEMLINE Y, BONNET D, SIDI D, BONHOEFFER P: Percutaneous
implantation of a biological valve in the aorta to treat aortic valve insufficiency – a sheep
study. Med Sci Monit 8: BR113-116, 2002.
CRIBIER A, ELTCHANINOFF H, BASH A, BORENSTEIN N, TRON C, BAUER F,
DERUMEAUX G, ANSELME F, LABORDE F, LEON MB: Percutaneous
10
transcatheter implantation of an aortic valve prosthesis for calcified aortic stenosis. First
human case description. Circulation 106: 3006-3008, 2002.
CRIBIER A, ELTCHANINOFF H, TRON CH, BAUER F, AGATIELLO C, SEBAGH
L, BASH A, NUSIMOVICI D, LITZLER PY, BESSOU JP, LEON MB: Early
experience with percutaneous implantation of heart valve prosthesis for the treatment of
end-stage inoperable patients with calcific aortic stenosis. J Am Coll Cardiol 43: 698-703,
2004.
DAVIES H: Catheter-mounted valve for temporary relief of aortic insufficiency. Lancet
I: 250, 1965.
FERRARI M, FIGULLA HR, SCHLOSSER M, TENNER I, FRERICHS I, DAMM C,
GUYENOT V, WERNER GS, HELLIGE G: Transarterial aortic valve replacement
with a selfexpanding stent in pigs. Heart 90: 1326-1331, 2004.
GRUBE E, LABORDE JC, ZICKMANN B, GERCKENS U, FELDERHOFF T,
SAUREN B, BOOTSVELD A, BUELLESFELD L, IVERSEN S: First report on a
human percutaneous transluminal implantation of a self-expanding valve prosthesis for
interventional treatment of aortic valve stenosis. Cathet Cardiovasc Interv 66: 465-469,
2005.
HANZEL GS, HARRITY PJ, SCHREIBER TL, O´NEILL WW: Retrograde
percutaneous aortic valve implantation for critical aortic stenosis. Cathet Cardiovasc
Interv 64: 322-326, 2005.
HARKEN DE, SOROFF HS, TAILOR WJ, LEFEMINE AA, GUPTA SK, LUNZER S:
Partial and complete prosthesis in aorta insufficiency. J Thorac Cardiovasc Surg 40:744762, 1960.
11
HILBERT SL, FERRANS VJ, TOMITA Y, EIDBO EE, JONES M: Evaluation of
explanted polyuretane trileaflet cardiac valve prostheses. J Thorac Cardiovasc Surg 94:
419-429, 1987.
HUBER CH, TOZZI P, CORNO AF, MARTY B, RUCHAT P, GERSBACH P,
NASRATULLA M, VON SEGESSER LK: Do valve stents compromise coronary flow ?
Eur J Cardio-thorac Surg 25: 754-759, 2004.
HUFNAGEL CA, HARVEY WP, RABIL PJ, MCDERMOT TF: Surgical correction of
aortic insufficiency. Surgery 35: 673-683,1954.
HUFNAGEL CA, HARVEY WP: The surgical correction of aortic regurgitation:
preliminary report. Bull Georgetown Univ Med Center 6: 3-6,1953.
LO HB, HEROLD M, REUL H, MUCKTER H, TAGUCHI K, SURMANN M,
HILDINGER KH, LAMBERTZ H, DE HAAN H, HANDT S: A tricuspid polyuretane
heart valve as an alternative to mechanical protheses or bioprostheses. ASAIO Trans 34:
839-844, 1988.
LUTTER G, KUKLINSKI D, BERG G, VON SAMSON P, MARTIN J, HANDKE M,
UHRMEISTER P, BEYERSDORF F: Percutaneous aortic valve replacement: an
experimental study.I. Studies on implantation. J Thorac Cardiovasc Surg 123:768-776,
2002.
MATSUBARA T, YAMAZOE M, TAMURA Y, OHSHIMA M, YAMAZAKI Y,
SUZUKI M, IZUMI T, SHIBATA A: Balloon catheter with check valves for
experimental relief of acute aortic regurgitation. Am Heart J 124: 1002-1008, 1992.
MOAZAMI N, BESSLER M, ARGENZIANO M, CHOUDHRI, AF, CABRERIZA SE,
ALLENDORF JD, ROSE EA, OZ MC: Transluminal aortic valve placement: a
12
feasibility study with a new designed collapsible aortic valve. ASAIO J 42: M381-M385,
1996.
MOULOPOULOS S, ANTHOPOULOS L, STAMATELOPOULOS S,
STEFADOUROS M: Catheter-mounted aortic valves. Ann Thorac Surg 11: 423-430,
1971.
MOULOPOULOS S: Catheter-mounted artificial heart valve for implanting in close
proximity to a defective natural heart valve. United States patent: Nr. 3 672 979, 1972.
MOULOPOULOS SD, ANTHOPOULOS LP, ANTONATOS PG, ADAMOPOULOS
PN, NANAS JN: Intra-aortic balloon pump for relief of aortic regurgitation:
experimental study. J Thorac Cardiovasc Surg 80: 38-44, 1980.
PAVCNIK D, UCHIDA B, TIMMERMANS H, KELLER FS, RÖSCH J: Square stent:
a new self expandable endoluminal device and its application. Cardiovasc Intervent
Radiol 24: 207-217, 2001.
PAVCNIK D, WRIGHT KC, WALLACE S: Development and initial experimental
evaluation of a prosthetic aortic valve for transcatheter placement. Radiology 183: 151154, 1992.
PHILIPS SJ, CIBORSKI M, FREED PS, CASCADE PN, JARON D: A temporary
catheter-tip aortic valve: hemodynamic effects on experimental acute aortic
insufficiency. Ann Thorac Surg 21: 134-137, 1976.
RUIZ CE, IEMURA M, MEDIE S, VARGA P, VAN ALSTINE WG, MACK S,
DELIGIO A, FEARNOT N, BEIER VH, PAVCNIK D, HIJAZI ZM, KIUPEL M:
Transcatheter placement of a low-profile biodegradable pulmonary valve made of small
intestine submucosa: a long-term study in a swine model. J Thorac Cardiovasc Surg 130:
477-484, 2005.
13
SOCHMAN J, PEREGRIN JH, PAVCNIK D, TIMMERMANS H, RÖSCH J:
Percutaneous transcatheter aortic disc valve prosthesis implantation: a feasibility study.
Cardiovasc Intervent Radiol 23: 384-388, 2000.
SOCHMAN J, PEREGRIN JH, ROCEK M, TIMMERMANS HA, PAVCNIK D,
RÖSCH J: Percutaneous one-step mechanical aortic disc prosthesis implantation: a
preliminary feasibility study in swine. Cardiovasc Intervent Radiol 29: 1149-9, 2006.
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Figure legends
Fig. 1
Ball and cage design for catheter-based aortic valve prosthesis deployment
Abbreviations: SC – Gianturco-Rösch Z stent carrier, B – ball, VR – valve ring for the
new orifice. In the left upper corner: scene from cinefluorography in systole,
in the right lower corner: in diastole. Pictures were supplied with a courtesy by D.
Pavcnik
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Fig.2 Mechanical disc valve design for two-step deployment
Abbreviations: SC – stent carrier (deployed in the first step), D – disc (deployed and
locked in the second step)
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Fig.3 Mechanical disc valve design for one-step deployment
Abbreviations: SC – SX braided stent carrier, DM – flexible disc membrane, LM –
locking mechanism
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Fig.4 Mechanical cone valve design for infracoronary positioning
Abbreviations: in the plain X-ray picture: SC – stent carrier, CV – cone valve struts.
In the pig model: AL – annular level (left ventricular outflow tract is below the line !)
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